After the death of his father the Schaaf family went to Bremen. They lived near the Weser Stadion. And so Thomas Schaaf came to SV Werder. He spent all his active and manager time with SV Werder. In 1972 he came to Werder Bremen's youth academy. 1978 he turned professional. Till 1994 he played 281 matches for Werder Bremen. He was with Bremen two times German Champion (1988, 1993) and two times Cup winner (1991, 1994). He also won the UEFA Cup in 1992. As player he played two times for the German U21 national team.

Schaaf began his coaching career during his active career. He was then coach of Werder's youth teams U17 (1987/88) and U19 (1988 - 1995). 1993 till 1995 he was assistance coach in the first team. After four years as coach with the second team he became coach of the first team in 1999. He is still coach. He is therefor the longest serving coach in today's German Bundesliga. As coach of the first team he won the German Bundesliga in 2004 and was three times Cup winner (1999, 2004, 2009). From 2004 his team qualified 5 times for the UEFA Champions League.

Thomas Schaaf is married and has a daughter. He is also engaged in social issues. He is ambassador for the "Zentrum für trauernde Kinder und Jugendliche " (center for mourning children and youths).